TransAlta (TAC) closed the last trading session at $8.05, gaining 9.2% over the past four weeks, but there could be plenty of upside left in the stock if short-term price targets set by Wall Street analysts are any guide. The mean price target of $13.12 indicates a 63% upside potential. The average comprises seven short-term price targets ranging from a low of $10.08 to a high of $19.18, with a standard deviation of $3.64. While the lowest estimate indicates an increase of 25.2% from the current price level ...